A:第五次反“围剿”的失败
B:中国社会主要矛盾的变化
C:国共关系由对峙走向缓和
D:抗日民族统一战线的建立
我国从免除学杂费、免费提供教科书,到免除农村寄宿生住宿费,不断改善农村中小学生学习生活条件,这主要是为了( )
如图表示某种兔迁入新环境后种群增长速率随时间变化的曲线.第3年时用标志重捕法调查该兔种群的密度,第一次捕获50只全部标志后释放,一个月后进行第二次捕捉,共捕获未标志的60只,标志的20只.则下列数字最接近K值的是( )
根据表格内容, 选择正确答案。
(B)
Wang Wei
I can't sing or dance. I can play the guitar. But I couldn't play it three years ago.
Alice
I can sing and dance. I can also play the piano. When I was six, I couldn't play the piano at all.
James
I can swim and cook. I can't draw pictures. I could swim when I was five years old.
Liu Fang
I can perform ballet and dance to disco. I can also sing English songs. But I couldn't sing English songs two years ago.
从爵士乐形成和发展的历史中,人们可以悟出什么道理?